Liquid-phase fluorination involves a mixture of corrosive reaction materials. The corrosion is acute especially where Lewis-acid catalysts, such as antimony halide catalysts, are used under high reaction pressures and at elevated temperatures. Under these conditions, strong acids form which tend to corrode reactor vessels, even those comprised of corrosion-resistant materials. Reactor corrosion compromises the structural integrity of the reactor and reduces its useful life. Therefore, a need exists to minimize reactor corrosion.
A recent approach to combat reactor corrosion involves lining or coating the inside of the reaction vessel with a fluoropolymer. Although effective in preventing chemical corrosion, the fluoropolymer component of the reactor tends to be problematic, especially for commercial-scale reactors, for example, over 500 gallons. Commonly-encountered problems include body flange seal leakage, liner flexing stresses, hydrogen fluoride permeation through the fluoropolymer liner, and blister formation. Such problems diminish the reactor's durability and lead to premature failure. Additionally, the fluoropolymer component tends to insulate the reactor thermally, necessitating costly and complex external heat transfer means and procedures.
Thus, a need exists for non-corroding reactor systems that can be used for the commercial-scale production of fluorinated compounds where high pressures are encountered and heat transfer is required.